def main():
    x = int(input())
    ans = "Yes" if x >= 30 else "No"
    print(ans)

if __name__ == "__main__":
    main() def main():
    x = int(input())
    ans = "Yes" if x >= 30 else "No"
    print(ans) main x = int(input()) x int(input()) int input() input ans = "Yes" if x >= 30 else "No" ans "Yes" if x >= 30 else "No" x >= 30 x 30 "Yes" "No" print(ans) print ans if __name__ == "__main__":
    main() __name__ == "__main__" __name__ "__main__" main() main def main():
    x = int(input())
    ans = "Yes" if x >= 30 else "No"
    print(ans) def main():
    x = int(input())
    ans = "Yes" if x >= 30 else "No"
    print(ans) main
def main():
    x = int(input())
    ans = "Yes" if x >= 30 else "No"
    print(ans)

if __name__ == "__main__":
    main()